In a wireless cellular network, such as a UTRAN (Universal Terrestrial Radio Access Network) and an EUTRAN (Evolved Universal Terrestrial Radio Access Network), to successfully receive a network service (such as network camping and data transmission), a terminal needs to perform a series of measurement and feedback on the network, such as measurement of carrier channel quality (such as carrier signal strength and signal quality), channel estimation (performed for data reception), and measurement and feedback of channel state information (CSI), where a physical signal on which the series of measurement and feedback, performed by the terminal, is based may be collectively referred to as a pilot signal.
In a traditional OFDM (Orthogonal Frequency Division Multiplexing) system, such as a release 8 of an LTE (Long Term Evolution) system, when mapping and sending of a transmission resource are performed on a pilot signal, full-bandwidth mapping and sending are performed on all pilot signals in a manner in which a quantity of pilots is maximized, that is, pilot signals on entire bandwidth (such as 20 MHz) are simultaneously used for channel measurement, channel estimation, and possible measurement of channel state information.
However, actually, when a terminal performs channel measurement or synchronization, pilots only on some resource blocks, not all pilots on full bandwidth in a frequency domain, are needed to meet a measurement precision requirement. In addition, on a premise of little allowed impact on performance, when demodulating data on a resource block, the terminal does not need to use a pilot signal on another resource block (such as a resource block without data) to perform channel estimation. Therefore, except the some resource blocks used for channel measurement or synchronization, when there is no data sent on other resource blocks, and the other resource blocks are not used for measuring channel state information, a pilot signal may not be sent.
Therefore, an existing manner of sending a pilot signal is likely to cause extremely large redundancy of pilot signals and lead to large pilot overheads.